Cellular wireless communication networks are ubiquitous in many parts of the world. Providing sufficient capacity and coverage in a cell is an ongoing challenge. In most cellular networks there are areas of high traffic, i.e., high concentration of users. In those areas the network operator would normally like to deploy additional capacity, to provide a satisfying user experience. The added capacity may be in the form of one or more additional macro base stations, or other nodes with low output power, which cover a relatively small area, in order to concentrate the capacity boost over only the area of increased user traffic.
Additionally, many cells have areas with relatively poor coverage (e.g., poor signal quality), where there is a need for coverage extension. Again, one way to accomplish improved coverage is to deploy a node with low output power, to concentrate the coverage boost in a small area.
In both cases, choosing nodes with relatively low output power minimizes the impact on the macro network. That is, the area in which the macro network may experience interference is minimized. Currently, there is a strong drive in the industry towards the use of low power nodes. These networks are known as Heterogeneous networks (“HetNets”), or multilayer networks. FIG. 1 depicts a network 10 in which a macro base station 12 provides wireless communication services over a wide area or cell 14. Additionally, low power nodes are deployed to provide additional capacity/coverage over small areas, for example pico base stations 16, relays 18, and home base stations, or femto cells 20.
Currently, areas with deficient capacity or coverage are discovered by network operator experience, or perhaps by customer complaints. In the case of poor coverage, there is some standardization effort ongoing to complement these methods. The standardization effort addresses the problem using User Equipment (UE) support. According to these methods, a UE should store its location when it loses coverage, and later when it again connects to the wireless network, the UE reports the occurrence of lost coverage and the position at which it occurred. However, since this solution relies on UE support—a feature that will probably be optional—it is unclear when such a solution may appear on the market. Therefore a network-based solution might be beneficial.
With a network-based method of determining areas needing additional capacity or experiencing poor coverage, the network operator has the opportunity to proactively address problematic areas, and avoid user complaints about dropped calls or poor performance.